The present disclosure relates to a vehicle seat, and particularly relates to a vehicle seat foldable by rotation of a rotary member disposed below a seat cushion in a direction toward the seat cushion.
Vehicle seats foldable in housing have been already well known. Of these foldable vehicle seats, a vehicle seat is configured to be foldable by rotation of a rotary member disposed below a seat cushion in a direction toward the seat cushion (see, e.g., Japanese Patent Publication JP 2007-302125A and Japanese Patent Publication JP 2014-172485A).
JP 2007-302125A describes a vehicle seat including, below a seat cushion, a front housing link as a rotary member. The vehicle seat described in JP 2007-302125A is now described. One end portion of the front housing link in a longitudinal direction thereof is rotatably supported, and the other end portion of the front housing link in the longitudinal direction thereof is rotatably supported on the seat cushion. The vehicle seat configured as described in JP 2007-302125A is folded by rotation of the front housing link in a direction toward the seat cushion. In a folded state of the vehicle seat, the seat cushion stacks on the front housing link, and a portion of the front housing link contacts an edge portion of a bottom portion of the seat cushion.
In the configuration in which the portion of the link contacts the edge portion of the seat cushion when the vehicle seat is folded, when reactive force (force acting on the link when the link contacts the edge portion) acting on the link from the edge portion increases, it becomes difficult to smoothly fold the vehicle seat. The edge portion of the seat cushion provides an influence on the outer appearance of the seat. For this reason, a configuration with an excellent design has been demanded as the configuration of the edge portion of the seat cushion. Moreover, even when the edge portion of the seat cushion is partially compressed due to contact with the link, such a compressed portion needs to be restored from a compressed state to an original state when the link is separated.
Moreover, a vehicle rear seat described in JP 2014-172485A includes a rotary link and a piston damper, an upper end of the rotary link being attached to a seat cushion side and a lower end of the rotary link being rotatably coupled to a vehicle floor side. It is configured such that in the operation of housing a seat body, the rotary link rotates toward a seat back side after a seat back has been folded to the seat cushion side, and in this manner, the seat body can be housed in a recessed housing portion. Moreover, the piston damper is configured such that biasing force is constantly applied to the seat cushion side. The piston damper supports a seat cushion from below, and assists the seat housing operation.
In the above-described link structure disclosed in JP 2014-172485A, the force of upwardly supporting the seat cushion from below by the piston damper is helpful in a seatable state, but decreases as the seat cushion rotates to a housed state. Specifically, in the seatable state in which the piston damper extends substantially in the vertical direction, an upward force component is great, and therefore, the supporting force is great. However, the piston damper inclines to the substantially horizontal direction while rotating to the housed state, and the upward force component decreases. Accordingly, the supporting force decreases.
According to the above-described configuration, when the seat cushion rotates from the seatable state to the housed state, the speed of rotation might increase, leading to great noise due to contact with a vehicle floor. In this case, while the seat cushion is rotating, if a user's hand supports the seat cushion not to increase the speed of rotation of the seat cushion, it is difficult to smoothly rotate the seat cushion. This leads to an unfavorable feeling of operation.
When the seat cushion is lifted such that the seat cushion rotates from the housed state to the seatable state, the supporting force of the piston damper is small as described above, and for this reason, sufficient rotation support cannot be provided. When the seat cushion rotates from the housed state to the seatable state, if the supporting force of the piston damper is set higher to provide the sufficient support, the seat cushion might unexpectedly rotate (lift) from the housed state due to oscillation in vehicle operation, for example.